| | | quote | Originally posted by cebix:
Yeah, voltage means nothing on a battery without load. So have you actually tried putting in a known good battery to see if the cars run good again? |
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Not often true.
Simple volts can show bad cell problems. I use a volt meter first then maybe double check if volts seems good.
Bad cell battery often make ~12v
but less then full charge volts. Then try to start then less even w/o a load active.
Most load testers are cheap (even Snap-on etc) and meter isn't very accurate. Unless a battery is toast often won't see problems. (Ignore most used them wrong to start with. Many even has directions on them but few bother to read.)
Better is a simple digital volt meter that shows 100th of a volt (0
.01 or less) to get accurate 10th (0
.1) volts reading.
Most battery I replace over the years had bad cells.
Some are dead from bad alt that over charge. If the system sees 15v or higher then battery and other parts can die too. Is why when you replace a battery check system volts w/ engine running to make sure new battery isn't overcharge. (Don't trust a dash meter. They often lie.)
Sulfate etc problems is often cars that sit like parked for winter. Parks cars have low current loads and will kill outright or drop charge level allowing cold weather to freeze them. Freezing = death even after they warm up. Best thing is pull the battery and store indoor. Even parked in a heated space, disconnect them.
[This message has been edited by theogre (edited 03-11-2017).]
